Hvac adjustment module

ABSTRACT

A heating, ventilation and air conditioning (HVAC) system is provided. The system includes an integrated motor including a plurality of operating speeds and an input for selecting one of the plurality of operating speeds. The system further includes a system controller and an adjustment module. The adjustment module includes a plurality of operating modes each associated with one of the plurality of operating speeds and the ability to manually vary associations between the plurality of operating modes and the plurality of operating speeds. The adjustment module selects one of the plurality of operating modes on the basis of control commands received from the system controller and setting programmed or manually entered into and stored in the adjustment module and controls the integrated motor according to the operating speed associated with the selected operating mode.

This is a divisional application of copending U.S. application Ser. No.13/352,515, filed Jan. 18, 2012, which claims the benefit of U.S.Provisional Application No. 61/433,701, filed Jan. 18, 2011, both ofwhich are incorporated herein by reference in their entirety.

BACKGROUND

The present exemplary embodiments relate generally to heating andcooling. They find particular application in conjunction with heating,ventilation, and air conditioning (HVAC) systems, and will be describedwith particular reference thereto. However, it is to be appreciated thatthe present exemplary embodiments are also amenable to other likeapplications.

By way of background, many residential and small commercial forced airHVAC systems employ Permanent Split Capacitor (PSC) motors and/or anElectronically Commutated Motors (ECMs) to drive blowers. These motorsgenerally include selectable speed taps for indoor speed control. Speedis determined by characteristics of the motor and system configurationparameters, such as duct size and installation, dampers and diffusers,HVAC system size, and the like.

Generally, operating modes for HVAC systems, such as heating, cooling,and constant fan operation, require different operating speeds of themotor. Namely, each operating mode generally has an optimum airflowand/or static pressure based on the physics of the heat exchangemechanism. In a heating mode it is based on a heat exchanger, in coolingmode it is based on a cooling coil, and in a fan mode is the slowestspeed that achieves good mixing and/or filtering of air and savesenergy, since the fan mode serves to even temperatures in a home andpush air through filters. Therefore, different taps and speeds aregenerally used for different operating modes.

The speeds used for different operating modes are normally selectedduring commissioning of the system by the installer. The installergenerally accomplishes this by making electrical connections to acontrol system, such that the desired tap and speed are energized by thecontrol system for the appropriate mode of operation (e.g., heating).One problem with this arrangement, however, is that once a tap and speedare selected, the installer has no control of the speed.

Limiting the installer's flexibility to set speed reduces or eliminatestheir ability to solve common system problems that can be correctedthrough precision airflow adjustment. For example, in the case ofheating, the temperature rise of air leaving a heat pump may be lessthan that leaving a furnace, thereby reducing comfort. This may beaddressable by slowing the air down and making it warmer coming out ofthe vents. As another example, in the case of cooling, an improperlyconfigured HVAC system may lead to low or high humidity levels, therebyreducing comfort.

The flow of air leaving an air conditioner may control humidity levels,where slowing airflow may increase dehumidification. Therefore, if one'shouse is close to water, the surrounding environment is likely toinclude high humidity, whereby more dehumidification is desirable.Similarly, if one lives in a dry area, such as Death Valley, thesurrounding environment is likely to include low humidity, whereby lessdehumidification is preferably.

Fixed speed PSC motors also might cause ductwork and air noise due tothe rapid startup of the motor. The rapid start up of the motor willalso cause uncomfortable drafts that are lessened using the inventionwhich provides gradual acceleration of the ECM blower motor to reducethe sudden surge of air in the ductwork.

The exemplary embodiment contemplates new and improved systems and/ormethods for remedying this and other problems.

BRIEF DESCRIPTION

Various details of the exemplary embodiment are hereinafter summarizedto provide a basic understanding. This summary is not an extensiveoverview of the disclosure and is intended neither to identify certainelements of the disclosure, nor to delineate the scope thereof. Rather,the primary purpose of the summary is to present certain concepts of thedisclosure in a simplified form prior to the more detailed descriptionthat is presented hereinafter.

The exemplary embodiment is primarily designed to be used as an ECMmotor replacement of a PSC motor or an upgrade of a PSC motor to an ECMmotor in existing HVAC systems and not for use in new factory assembledHVAC systems.

The exemplary embodiment is designed to provide a compatible replacementmotor and control for a wide variety of installed HVAC systems and alsoincorporates the existing thermostat control and furnace safetycircuits.

The exemplary embodiment also allows the installer to tune the airflowof an HVAC system to correct airflow problems that cannot by correctedwith an HVAC system using a fixed speed PSC blower motor.

According to one aspect of the exemplary embodiment, a variable speedblower motor unit controlled by a heating, ventilation and airconditioning (HVAC) system controller. The variable speed blower motorunit may include an integrated motor including a plurality of operatingspeed ranges and an input for selecting one of the plurality ofoperating speed ranges. The variable speed blower motor unit may furtherinclude an adjustment module coupled to the integrated motor and theHVAC system controller. The adjustment module may include a plurality ofoperating modes each associated with one of the plurality of operatingspeeds. The adjustment module selects one of the plurality of operatingmodes on the basis of control commands received from the HVAC systemcontroller and controls the integrated motor according to the operatingspeed associated with the selected operating mode. Further, theadjustment module includes the ability to manually vary associationsbetween the plurality of operating modes and the plurality of operatingspeeds.

According to another aspect of the exemplary embodiment, a heating,ventilation and air conditioning (HVAC) system is provided. The systemincludes an integrated motor including a plurality of operating speedsand an input for selecting one of the plurality of operating speedranges. The system further includes a system controller and anadjustment module. The adjustment module includes a plurality ofoperating modes each associated with one of the plurality of operatingspeeds and the ability to manually vary associations between theplurality of operating modes and the plurality of operating speeds. Theadjustment module selects one of the plurality of operating modes on thebasis of control commands received from the system controller andcontrols the integrated motor according to the operating speedassociated with the selected operating mode.

According to another aspect of the exemplary embodiment, a method forcomputing and reporting cubic feet per minute (CFM) of airflow of amotor operating at an operating speed and operating torque is provided.The method may include: modeling CFM of the motor as a function of motortorque to create a CFM model; calculating a ratio of the operating speedto a base speed of the motor; calculating a base torque of the motor atthe base speed from the ratio and the operating torque; calculating abase CFM of the motor from the base torque and the CFM model; and/orcalculating an operating CFM of the motor at the operating speed usingthe base CFM and the ratio.

According to another aspect of the exemplary embodiment, a variablespeed blower motor unit controlled by a heating, ventilation and airconditioning (HVAC) system controller is provided. The variable speedblower generally includes: an integrated motor including a plurality ofoperating speeds or torques and an input for selecting one of theplurality of operating speeds or torques; and, an adjustment modulecoupled to the integrated motor and the HVAC system controller, whereinthe adjustment module includes a plurality of operating modes eachassociated with one of the plurality of operating speeds or torques.Optionally, the adjustment module typically selects one of the pluralityof operating modes on the basis of control commands received from theHVAC system controller and controls the integrated motor according tothe operating speed associated with the selected operating mode, and/orthe adjustment module may include the ability to manually varyassociations between the plurality of operating modes and the pluralityof operating speeds or torques. Further, the adjustment module maydisplay operating CFM of the integrated motor as determined using amethod such as the one in the preceding paragraph.

According to another aspect of the exemplary embodiment, a method forcomputing and reporting static pressure (SP) of a motor operating at anoperating speed and operating torque is provided. The method mayinclude: modeling SP of the motor as a function of motor torque tocreate a SP model; calculating a ratio of the operating speed to a basespeed of the motor; calculating a base torque of the motor at the basespeed from the ratio and the operating torque; calculating a base SP ofthe motor from the base torque and the SP model; and/or, calculating anoperating SP of the motor at the operating speed using the base SP andthe ratio.

According to yet another aspect of the exemplary embodiment, a variablespeed blower motor unit controlled by a heating, ventilation and airconditioning (HVAC) system controller is provided. The variable speedblower may include, for example: an integrated motor including aplurality of operating speeds or torques and an input for selecting oneof the plurality of operating speeds or torques; and/or an adjustmentmodule coupled to the integrated motor and the HVAC system controller,wherein said adjustment module includes a plurality of operating modeseach associated with one of the plurality of operating speeds ortorques. Optionally, the adjustment module may selects one of theplurality of operating modes on the basis of control commands receivedfrom the HVAC system controller and controls the integrated motoraccording to the operating speed associated with the selected operatingmode, and/or the adjustment module may include the ability to manuallyvary associations between the plurality of operating modes and theplurality of operating speeds or torques. Further, the adjustment modulemay display operating SP of the integrated motor as determined using,for example, the method described in the preceding paragraph.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and drawings set forth certain illustrativeimplementations of the disclosure in detail, which are indicative ofseveral exemplary ways in which the various principles of the disclosuremay be carried out. The illustrative examples, however, are notexhaustive of the many possible embodiments of the disclosure. Otherobjects, advantages and novel features of the disclosure will be setforth in the following detailed description of the disclosure whenconsidered in conjunction with the drawings, in which:

FIG. 1 is a block diagram of an HVAC system according to aspects of theexemplary embodiment;

FIG. 2 is a state diagram of an adjustment module;

FIG. 3 is an adjustment module according to aspects of the exemplaryembodiment;

FIG. 4 is the adjustment module FIG. 3 with a protective cover;

FIG. 5 is a graph of a corpus of data points representing the relationbetween cubic feet per minute (CFM) and torque at a speed of 1000 RPM;

FIG. 6 is a physical explanation of a method to solve for the torqueneeded to get a specific CFM; and,

FIG. 7 is a graph of a corpus of data points representing the relationbetween static pressure (SP) and torque at a speed of 1000 RPM.

DETAILED DESCRIPTION

One or more embodiments or implementations are hereinafter described inconjunction with the drawings, where like reference numerals are used torefer to like elements throughout, and where the various features arenot necessarily drawn to scale.

With reference to FIG. 1, a block diagram of an HVAC system 100according to aspects of the exemplary embodiment is provided. The HVACsystem 100 suitably belongs to one or more of the following groups ofHVAC systems: residential split and package systems; natural gas,propane, and oil heat furnace systems; dual fuel systems; hot water coiland geothermal air handler systems; and the like.

As will be seen, the HVAC system 100 provides for manual adjustment ofblower motor speed and/or torque advantageously allowing higherprecision airflow selection, thereby giving the installer or maintenancetechnician the ability to compensate for system performance problems.For example, as noted above, the installer or maintenance technician maycompensate for humidity problems.

The system 100 may include one or more of an integrated motor 102, asystem controller 104, an adjustment module 106, and the like. Incertain embodiments, the adjustment module 106 may be combined with theintegrated motor 102. Alternatively, or in addition, in certainembodiments, the system controller 104 and the adjustment module 106 maybe one and the same.

The integrated motor 102 drives a blower operatively connected theretoto move air through a ventilation system of the HVAC system 100. Incertain embodiments, the blower may be a direct-drive centrifugalblower. The integrated motor 102 may include one or more of a variablespeed motor, such as a PSC and PSC speed controller or ECM motor, amotor driver, and the like. Further, the integrated motor 102 need nothave a braking function, whereby the integrated motor 102 may stop via amotor coast down.

The integrated motor 102 is suitably receptive to speed commands and/ortorque commands. Speed commands may adjust the operating speed of theintegrated motor 102, and torque commands may adjust the operatingtorque of the integrated motor 102. Further, speed commands and/ortorque commands may be embodied by control signal 107, such as a pulsewidth modulated signal, an analog signal, such as 4-20 mA or 0-10V,serial communications, a CDMA cell phone call, 802.11 wireless Ethernetprotocol, GPIB, MODBUS, and the like. In certain embodiments, theintegrated motor 102 may further be receptive to a direction command.Direction commands may adjust the direction of the integrated motor 102(i.e., clockwise or counter-clockwise) and/or may be embodied bydirection signal 109, such as a binary signal, an analog signal, awireless signal, and the like.

Beyond commands, the integrated motor 102 suitably receives power fromthe system controller 104. However, in other embodiments, the integratedmotor 102 may receive power from another source, such as the adjustmentmodule 106, the HVAC system power source, an external power source, andthe like.

The integrated motor 102 suitably outputs one or more of a fault signal108, a motor ready signal 110, a speed signal 112, a torque signal (notshown), and the like. The fault signal 108 suitably indicates a faultwith the integrated motor 102 and may be embodied by a binary signal, ananalog signal, a wireless signal, or the like. The motor ready signal110 suitably indicates the horse power of the integrated motor 102and/or may be embodied by a constant square wave with a duty cycleproportional to the horse power rating of the integrated motor 102, adigital signal, an analog signal, a wireless signal, or the like. Thespeed signal 112 suitably indicates the speed of the integrated motor102 (e.g., revolutions per minute (RPM)) and/or may be embodied by aconstant square wave with a frequency proportional to the speed of theintegrated motor 102, a digital signal, an analog signal, a wirelesssignal, or the like. The torque signal suitably indicates the torque ofthe integrated motor 102 and/or may be embodied by a constant squarewave with a frequency proportional to the torque of the integrated motor102, a digital signal, an analog signal, a wireless signal, or the like.

The system controller 104 controls the HVAC system 100 and provides theadjustment module 106 with control commands. The control commandssuitably instruct the adjustment module 106 as to the operating mode ofthe HVAC system 100, such as heating, and use one or more signals 113.To set the operating mode of the HVAC system 100, the system controller104 suitably includes one or more user input devices allowing selectionof the operating mode. The user input devices may include one or more ofa button, a switch, a toggle, a slider, and the like.

Additionally or alternatively, a thermostat of the system controller 104may set the operating mode of the HVAC system 100. For example, incertain embodiments, the signals 113 include one or more signalsgenerated by the thermostat of the system controller 104, such as one ormore of W, Y, G, W1, W2, Y1, Y2, and the like. Y corresponds to cooling,Y1 corresponds to a first cooling stage, Y2 corresponds to a secondcooling state, W1 corresponds to a first heating stage, and W2corresponds to a second heating stage.

Additionally or alternatively, the system controller 104 may include oneor more sensors and/or a processor implementing a state machine orprogram to set the operating mode of the HVAC system 100. In suchembodiments, the operating mode may be set on the basis of the sensors,the state machine, or a combination of the two. For example, the HVACsystem 100 may enter a heating operating mode if a sensed temperaturefalls below a threshold.

In certain embodiments, the system controller 104 may include one ormore tap connectors 114, such as five tap connectors. The tap connectors114 are suitably provisioned to connect to taps of a motor, such as aPermanent Split Capacitor (PSC) motor and/or an ElectronicallyCommutated Motor (ECM), where each tap connector may activate adifferent motor speed. Further, the tap connectors 114 are suitablymapped to operating modes (e.g., heating, cooling, etc.) of the HVACsystem 100 by the system controller 104, whereby the tap connectors 114are generally activated on the basis of operating mode.

In embodiments where the system controller 104 includes the tapconnectors 114, the tap connectors 114 are suitably not used to controlthe speed of the integrated motor 102, as is common in typical HVACsystems. Rather, the tap connectors 114 are employed to power theintegrated motor 102. Namely, at least one of the tap connectors willgenerally be activated whenever the HVAC system 100 is in an operatingmode requiring the blower. Therefore, ORing the tap connectors 114together and using the output thereof can be used to power theintegrated motor 102. An activated tap connector generally provides 120Vor 240V, up to 15A. Additionally or alternatively, the tap connectors114 are employed to provide control commands to the adjustment module106 via the signals 113. Alternatively, the motor can receive powerdirectly from the main power source and the ORed taps can be used tosignal the adjustment module that the system controller requires thatthe motor be energized.

The adjustment module 106 controls the integrated motor 102 on the basisof control commands. The control commands are suitably received from thesystem controller 104 and/or the system thermostat and include theoperating mode of the HVAC system 100, such as heating. Further, thecontrol commands may be embodied by one or more signals 113 andalternatively 114, such as analog signals, digital signals, wirelesssignals, and other like signals. When a control command is received, theadjustment module 106 suitably instructs the integrated motor 102 to runat an associated speed, torque, airflow, or static pressure.

In certain embodiments, the control commands may be received via one ormore command inputs 116, each corresponding to a different speed,torque, airflow, or static pressure of the integrated motor 102(collectively referred to as the “operating settings”). Preferably, butnot necessarily, five commands inputs are employed. When one of thecommand inputs is activated, the adjustment module 106 suitablyinstructs the integrated motor 102 to run at the associated speed,torque, airflow, or a static pressure mode. Activation may beaccomplished by providing 24V, but other means are appropriate.Suitably, if more than one command input is activated, the command inputwith the greatest associated speed, torque, airflow or static pressuremay be chosen. However, it is contemplated that if more than one commandinput is activated, the integrated motor 102 may not run, therebysimulating a failure of a PSC motor.

Advantageously, employing the command inputs 116, may allow aninstallation and/or maintenance technician to map operating modes tovarying speeds, torques, airflows, or static pressures using signalsfrom a thermostat. For example, the installation and/or maintenancetechnician may associate a signal from a thermostat of the systemcontroller 104 that activates upon the need for cooling with one of thecommand inputs 116 associated with the appropriate speed for cooling.Further, employing the command inputs 116 allows the installation and/ormaintenance technician to easily retrofit an existing HVAC system.

To control the integrated motor 102, the adjustment module 106translates the control commands to speed commands or torque commands andthen provides the speed commands or torque commands to the integratedmotor 102. In instances where a control command is associated with anairflow or static pressure, the adjustment module 106 translates theairflow or static pressure to a speed or torque, which is then providedto the integrated motor 102 as a speed command or torque command.Whether speed commands or torque commands are employed is dependent uponwhether the adjustment module 106 is in a torque mode, a speed mode, anairflow mode, or a static pressure mode. Suitably, but not necessarily,torque commands are used when in an airflow mode or static pressuremode.

The speed commands suitably range from the minimum rated motor speed tothe maximum rated motor speed. For example, for a ½ HP, the motormaximum speed may be 1200 revolutions per minute (RPM), and for a ¾ HPmotor, the maximum speed may be 1400 RPM. Similar to the speed commands,the torque commands suitably range from the minimum rated motor torqueto the maximum rated motor torque. For a ½ HP motor, the maximum torquemay be 42 oz-ft and the minimum torque may be 1 oz-ft.

In certain embodiments, the adjustment module 106 may delay providingspeed commands or torque commands to the integrated motor 102 until theintegrated motor has started. This determination may be made using themotor ready signal 110 from the integrated motor, since this signal 110is only active when the integrated motor 102 has power. Other means ofdetermining when the integrated motor 102 has started are, however,equally amenable.

To translate control commands to speed commands and/or torque commands,the adjustment module 106 suitably turns to a lookup table. Namely, whena control command specifying the state of the HVAC system 100 isreceived, the adjustment module 106 suitably looks for the correspondingstate in the lookup table to determine the appropriate operating speed,operating torque, operating flow, or operating pressure of theintegrated motor 102 and/or the direction of the integrated motor 102.Additionally, where the looked up value is an operating flow oroperating pressure, the adjustment module 106 suitably translates theoperating flow or operating pressure to an operating speed or operatingtorque. For details pertaining to this translation, attention isdirected to the following discussion of FIGS. 5-7. The lookup table issuitably stored on a local memory of the adjustment module 106.

Additionally or alternatively, to translate control commands to speedcommands and/or torque commands, an operating speed and/or an operatingtorque may be determined using data from one or more sensors, such astemperature sensors, pressure sensors, flow sensors, and the like. Forexample, an operating speed and/or an operating torque may be based ontemperature, output temperature, temperature rise or drop, and the like.In such embodiments a PID controller may be employed to actively adjustthe operating speed and/or operating torque.

To provide the speed commands and/or torque commands to the integratedmotor 102, speed commands and/or torque commands are suitably embodiedby a pulse width modulated (PWM) signal. However, other means ofproviding the speed commands are equally amenable. For example, thespeed commands and/or the torque commands may be provided by way of ananalog signal, such as 4-20 mA or 0-10V, serial communications, a CDMAcell phone call, 802.11 wireless Ethernet protocol, GPIB, MODBUS, andthe like.

In embodiments employing a PWM signal, the relationship between motorspeed (specified in revolutions per minute (RPM)) and PWM duty cyclemay, but not necessarily, be defined as RPM=(1250×duty cycle)+275.Further, the PWM signal may include one or more of a frequency of 80 Hz,a duty cycle ranging from 6% to 100%, a minimum speed of 350 RPM, 24 V,and the like. Alternatively, the relationship between motor torque(specified in ounce-feet (Oz-Ft)) and PWM duty cycle may, but notnecessarily, be defined as Oz-Ft=PWM duty cycle %−10%. Further, the PWMsignal may include one or more of a frequency of 80 Hz, a duty cycleranging from 6% to 100%, a minimum torque of 5 Oz-Ft, 24 V, and thelike.

Beyond control commands, the adjustment module 106 suitably receivespower from the system controller 104. However, in other embodiments, theadjustment module 106 may receive power from another source. Forexample, the adjustment module 106 may receive power directly from autility grid. In certain embodiments, the power may include 24V and oneof 50 Hz and 60 Hz power.

The adjustment module 106 may further receive one or more of the speedsignal 112, the motor ready signal 110, the fault signal 108, and thelike from the integrated motor 102. These signals 108, 110, 112 may bedigital, analog, or a combination of the two. Further, these signals108, 110, 112 may be embodied by binary signals, analog signals, digitalsignals, wireless signals, and the like.

In embodiments in which the speed signal 112 is received, the adjustmentmodule 106 may compare the speed of the integrated motor 102, asspecified by the speed signal 112, against the speed provided to theintegrated motor 102 via speed commands. If there is a substantialvariance, the adjustment module 106 may perform one or more actions,such as disabling the integrated motor 102, increasing the speed sent tothe integrated motor 102, generating an audio and/or visual indication,and the like. Additionally, or alternatively, the adjustment module 106may display the speed of the integrated motor 102 using the speed signal112 on a display of the adjustment module 106. The display may includeone or more of an LCD, a CRT monitor, one or more LEDs, a projector, andthe like. Further, the adjustment module 106 suitably updates thedisplay of the operating speed of the integrated motor 102 no less than1 time per second.

In embodiments in which the torque signal is received, the adjustmentmodule 106 may compare the torque of the integrated motor 102, asspecified by the torque signal, against the torque provided to theintegrated motor 102 via torque commands. If there is a substantialvariance, the adjustment module 106 may perform one or more actions,such as disabling the integrated motor 102, increasing or decreasing thetorque command sent to the integrated motor 102, generating an audioand/or visual indication, and the like. Additionally, or alternatively,the adjustment module 106 may display the torque of the integrated motor102 using the torque signal on a display of the adjustment module 106.The display may include one or more of an LCD, a CRT monitor, one ormore LEDs, a projector, and the like. Further, the adjustment module 106suitably updates the display of the operating torque of the integratedmotor 102 no less than 1 time per second.

In embodiments in which the fault signal 108 and/or the motor readysignal 110 are received, the adjustment module 106 may display the faultstatus of the integrated motor 102 and/or whether the integrated motor102 is stopped. As noted above, the motor ready signal 110 is onlyactive when the integrated motor 102 is active. The fault signal 108and/or the motor ready signal 110 may be displayed on the displaydiscussed for the speed signal 112 and/or the torque signal. However,the fault signal 108 and/or the motor ready signal 110 are preferablydisplayed using one or more light sources, such as LEDs.

In certain embodiments, the adjustment module 106 may include theability to adjust the operating direction of the integrated motor 102.To adjust the operating direction of the integrated motor, theadjustment module 106 suitably includes one or more user input devices,such as a switch toggling between clockwise and counter clockwise.Adjusting the direction of the motor rotation to operate in the correctdirection is required for proper operation of the blower. These userinput devices may control direction commands provided to the integratedmotor via the direction signal 109.

Additionally or alternatively, in certain embodiments, the adjustmentmodule 106 may include the ability to adjust whether speed commands ortorque commands are provided to the integrated motor 102. To adjustwhether speed commands or torque commands are provided to the integratedmotor 102, the adjustment module 106 suitably includes one or more userinput devices, such as a switch toggling between speed mode and torquemode. Notably, however, such a selection is not necessary. For example,in certain embodiments, the adjustment module may allow a hybrid ofspeed commands and torque commands, whereby there is no defined speedmode and torque mode to toggle between.

Additionally or alternatively, in certain embodiments, the adjustmentmodule 106 may include the ability to adjust one or more of operatingspeeds, operating torques, operating pressure, operating airflow, andthe like of the lookup table (i.e., the operating settings). To adjustthe operating settings, the adjustment module 106 suitably includes oneor more user input devices, such as buttons, switches, and the like.Additionally, or alternatively, in certain embodiments, the HVAC system100 may need to enter an operating mode to adjust the associatedoperating setting.

The user input devices suitably allow the installation and/ormaintenance technician to adjust factory default operating settings upto a predetermined number (e.g., 150 RPM when speed is involved), up ordown from default values to tune the operating setting for the specificinstallation/application. The predetermined number is suitably selectedto keep the context of LO to HI still valid since installation and/ormaintenance technicians will expect each to cover different ranges.Alternatively, the adjustment module 106 may include the ability toadjust the operating direction of the integrated motor 102 and/oroperating torques of the lookup table. In certain embodiments, theinstallation and/or maintenance technician may adjust factory torquedefaults up to predetermined number of Oz-Ft, such as 15 Oz-Ft, up ordown from default values to tune the speed for the specificinstallation/application. The predetermined number is suitably selectedto keep the speed context of LO to HI still valid since installationand/or maintenance technicians will expect each to cover differentranges.

To illustrate, the user input devices may include a “Program” button, an“Up” button, and a “Down” button. In such embodiments, an installationand/or maintenance technician may select the “Program” button of theadjustment module 106 to enter an edit mode. Once in the edit mode, theinstallation and/or maintenance technician may then select the “Up”and/or the “Down” buttons to increase and/or decrease the operatingsetting in predetermined increments, such as increments of 10 RPM. Whenthe adjustments are complete, the installation and/or maintenancetechnician may then press the “Program” button again to exit the editmode.

Additionally or alternatively, in certain embodiments, the adjustmentmodule 106 may include the ability to reset any field modified settingsto factory defaults. Namely, the adjustment module 106 may include auser input device, such as a button, allowing one to reset the operatingsettings to factory defaults. As should be appreciated, this is usefulfor situations in which an installation and/or maintenance technicianwishes to start over in their efforts to configure the HVAC system 100.

Additionally, or alternatively, in certain embodiments, the adjustmentmodule 106 may include a protection mechanism to prevent the HVAChomeowner or user from changing the operating settings. For example, theadjustment module 106 may include one or more of a protective cover, apass code, a key, and the like.

Additionally, or alternatively, in certain embodiments, the adjustmentmodule 106 may include the ability to set an operating setting (e.g.,speed or torque) over a predetermined period of time. In other words,the adjustment module 106 may include the ability to adjust the rate ofchange the integrated motor 102 will apply when changing from one speedor torque to another. For example, the adjustment module 106 maygradually change from a first motor speed or torque to a second motorspeed or torque over a period of time, such as 30 seconds. As anotherexample, the adjustment module 106 may gradually change from an offposition to a cooling speed or torque, such as 1000 RPM or 30 oz-ft,over a period of 30 seconds. In certain embodiments, the rate employedmay be 25 RPM per second.

Additionally, or alternatively, in certain embodiments, the adjustmentmodule 106 may include a switch for enabling “constant blower”operation. This switch maintains the blower in a constant speed, torque,airflow or static pressure.

With reference to FIG. 2, a state diagram 200 that may be employed bythe adjustment module 106 is provided. The state diagram 200 includes asystem off state 202, an adjustment module power state 204, a stop state206, a run mode fan state 208, run mode (any speed) states 210, programmode states 212, a reset mode state 214, and the like.

The adjustment module 106 is suitably in the system off state 202 whenthere is no power to the HVAC system 100. This may be due to, forexample, power loss or a technician servicing the system 100. In thisstate 202, the adjustment module 106 does nothing because there is nopower. To exit this state 202, power must generally be supplied.

The adjustment module 106 enters the adjustment module power state 204when it was previously in the system off state 202 and the HVAC system100 has been powered up. In certain embodiments, the adjustment module106 receives 24V when the HVAC system 100 is powered up. In theadjustment module power state 204, the adjustment module 106 may startupand/or initializes itself. This may include, for example, reading and/ordisplaying an operating mode. To exit this state 204, any startup and/orinitialization tasks must generally be completed.

The adjustment module 106 enters the stop state 206 when it waspreviously in the adjustment power state 204 and the system 100 does notrequire blower operation. In this state 206, the adjustment module 106suitably waits for control commands and/or a motor power signal. Theadjustment module 106 suitably exits this state 206 upon receipt of amotor power signal. In certain embodiments, the motor power signal maybe the motor ready signal, discussed above.

The adjustment module 106 enters the run mode fan state 208 when theadjustment module 106 was previously in the stop state 206 and theintegrated motor 102 is starting blower operation and/or the adjustmentmodule 106 receives control commands to run in a constant fan operatingmode. In this state 208, the integrated motor 102 is suitably run at aconstant speed, torque, airflow, or static pressure in accordance with afan operating mode. The adjustment module 106 suitably exits this state208 upon loss of motor power, selection of a programming mode (e.g.,depression of the select button, discussed above), selection of anoperating mode other than fan mode, or the like.

The adjustment module 106 enters the run mode (any speed) states 210 ifthe adjustment module 106 was previously in the run mode fan state 208and a request for a different operating mode is made. For example, arequest is made for a heating operating mode. In these states 210, theadjustment module 106 suitably controls the integrated motor 102 inaccordance with the operating setting associated with the operatingmode. The adjustment module 106 suitably exits these states 210 uponloss of motor power, selection of a programming mode, selection of anoperating mode other than the present operating mode, or the like.

The adjustment module 106 enters program mode states 212 if theadjustment module 106 was previously in the run mode fan state 208 orthe run mode (any speed) states 210 and a technician is adjusting blowerspeed for the present operating mode. A technician may adjust the blowerspeed by, for example, pressing a select button while in a run mode. Inthese states 212, the technician may adjust the operating settingassociated with the current run mode. To exit these states 212, thetechnician takes appropriate action exit these states 212. For example,the technician may select a button.

The adjustment module 106 enters the reset state 214 if, for example, areset button is depressed while in a program mode. Suitably, thisoperating mode restores factory default settings to the adjustmentmodule 106. When the restoration is complete, the adjustment module 106may return to program mode.

With reference to FIG. 3, an adjustment module 300 according to aspectsof the exemplary embodiment is provided. The adjustment module 300 is amore specific embodiment of the adjustment module 106 of FIG. 1.Therefore, the discussion heretofore is equally amenable to thediscussion to follow and components described hereafter are to beunderstood as paralleling like components discussed heretofore, unlessnoted otherwise.

The adjustment module 300 suitably instructs an associated integratedmotor as to a speed or torque to use, where these instructions are basedon input from one or more command inputs, such as the command inputs 116of FIG. 1. Each command input may correspond to a different speed,torque, airflow, or static pressure for the integrated motor(collectively referred to as the “operating settings”). Airflow andstatic pressure are suitably translated to speed or torque in accordancewith the discussion of FIGS. 5-7.

When one of the command inputs is activated, the adjustment module 300suitably instructs the integrated motor to run at the associatedoperating setting. Activation may be accomplished by providing 24V, butother means are appropriate. The adjustment module 300 may furtherinstruct the associated integrated motor as to operating direction.

The adjustment module 300 suitably allows adjustment of operatingsettings associated with the one or more command inputs. To facilitatesuch a modification, the adjustment module 300 may include one or moreoperating mode light sources 302, one or more tuning user input devices304, a direction user input device 306, an operating setting display308, a fault light source 310, and the like.

The operating mode light sources 302 suitably provide an indication asto which of the command inputs are activated. Further, each of theoperating mode light sources 302 suitably corresponds to a differentcommand input. Command inputs may include one or more of run, high,medium-high, medium low, low, constant, and the like. The operating modelight sources 302 may include one or more LEDs, fluorescent lights,halogen lights, and the like.

The tuning user input devices 304 suitably allow a user of theadjustment module 300 to change operating settings associated with thecommand inputs. Suitably, the tuning user input devices allow a user ofthe adjustment module 300 to increase and/or decrease the operatingsetting associated with the present activated command input. The tuninguser input devices 304 may include one or more of buttons, switches, andthe like.

In certain embodiments, the tuning user input devices 304 may includeone or more of a select button 304 a, an up button 304 b, a down button304 c, and the like. In such embodiments, an installation and/ormaintenance technician may select the select button 304 a of theadjustment module 300 to enter an edit mode for the presently activatedcommand input. Once in the edit mode, the installation and/ormaintenance technician may then select the up button 304 b and/or thedown button 304 c to increase and/or decrease the operating setting inpredetermined increments, such as increments of 10 RPM or 1 oz-ft. Whenthe adjustments are complete, the installation and/or maintenancetechnician may then press the select button 304 a again to exit the editmode.

The direction user input device 306 suitably allows a user of theadjustment module 300 to change the operating direction of theassociated integrated motor. Namely, the direction user input device 306suitably allows a user of the adjustment module 300 to specify whetherthe associated integrated motor runs in a clockwise or counter clockwisedirection. The direction user input device 306 may include a switch, oneor more buttons, and the like. Adjusting the direction of the motorrotation to operate in the correct direction is required for properoperation of the blower.

In certain embodiments, one or more of the operating mode light sources302, the tuning user input devices 304, the direction user input device306, and the like may be protected from tampering by a home user of theadjustment module 300 as shown in FIG. 4. Namely, the adjustment module300 module may include a protective cover 312 as shown in FIG. 4.

Referring back to FIG. 3, the operating setting display 308 suitablydisplays a speed, torque, airflow, or static pressure of the associatedintegrated motor as reported to the adjustment module 300. In certainembodiments, the adjustment module 300 may receive a speed signal or atorque signal from the associated integrated motor specifying thecurrent speed or current torque of the integrated motor. Where theoperating setting is airflow or static pressure, the torque or speedspecified by the torque signal or speed signal may be translated toairflow or static pressure as described in connection with FIGS. 5-7.

The operating setting display 308 may display a graphical representationof the calculated airflow or static pressure, the speed signal, or thetorque signal using, for example, numerical characters. The operatingsetting display 308 suitably includes an LCD display, but other displaysare equally amenable. For example, the operating setting display 308 mayinclude a CRT display, a projection based display, an LED display, andthe like.

The fault light source 310 suitably indicates when a fault is occurswith the associated integrated motor. In certain embodiments, theadjustment module 300 may receive a fault signal from the integratedmotor and control the fault light source 310 on the basis of thissignal. The fault light sources 310 may include one or more LEDs,fluorescent lights, halogen lights, and the like.

Alternatively, all of the display items (302, 306 and 308) may becombined into a single graphical or numeric display, such as an LCDdisplay, an Organic LED display, or a Vacuum Fluorescent display.

In certain embodiments the system can be configured to enableprogramming of the ECM motor to cause the blower to produce a particularair flow rate of cubic feet per minute (CFM). This can be accomplishedby measuring the CFM directly with appropriate instruments (e.g., flowmeters, etc.) at a particular speed (rpm) of the motor and causing thespeed and CFM to be recorded in the control memory. This operation willestablish the correct relation of rpm per CFM, which can be used tocalculate the required speed that will produce any value of CFM withinthe operating range of the blower. Alternatively, the CFM can becalculated using blower wheel dimensional constants and static pressureat a particular blower motor speed.

According to additional aspects of the exemplary embodiment, methods tosolve for CFM from known speeds and torque, to solve for SP from knownspeeds and torque, to solve for the torque needed to get a specific CFM,and to solve for the torque needed to get a specific SP are provided.Briefly, the methods require knowledge of the polynomial equations thatdescribe the CFM and/or the SP of the motor in terms of the motor torqueat a “Base Speed” (normally 1000 rpm) and the Affinity Laws for Fans.Further, it is assumed that the motor speed can be accurately measuredand/or the torque can be accurately determined, usually by operating themotor in a “constant-torque” mode.

Before discussing the methods in detail, it is to be understood that thefollowing variables are defined as follows.

-   -   N_(b)=the base speed used in the calculations (this is 1000 rpm)    -   T_(b)=the base torque at 1000 rpm and a specific CFM or SP    -   CFM_(b)=the base CFM at 1000 rpm and a specific T_(b) or SP    -   SP_(b)=the base SP at 1000 rpm and a specific T_(b) or CFM    -   N_(x)=the blower wheel speed in rpm at the operating speed    -   T_(x)=the blower motor torque at the operating speed    -   CFM_(x)=the output CFM of the blower at the operating speed    -   SP_(x)=the blower static pressure at the operating speed    -   R=ratio of operating speed to the base speed    -   T_(p)=Programmed torque in OzFt    -   N_(m)=Measured speed at programmed torque T_(p)

The method to solve for CFM from known speeds and torque includesmodeling motor CFM as a function of motor torque. Suitably, CFM as afunction of torque is modeled using a third-order polynomial as follows:

CFM _(b) =A ₁(T _(b))³ +B ₁(T _(b))² +C ₁(T _(b))+D ₁,   (1)

where A₁, B₁, C₁, and D₁ are coefficients unique to the fan or blowerwheel. However, higher and/or lower order polynomials are contemplated.Regardless of the order of the polynomial employed, modeling entailsdetermining the coefficients A₁, B₁, C₁, D₁.

To solve for the coefficients, a polynomial trend line of the desiredorder is fit to a corpus of data points representing the relationbetween CFM and torque. Suitably, these data points are empiricallydetermined through testing. With reference to FIG. 5, a corpus of datapoints representing the relation between CFM and torque is illustrated.Further illustrated in FIG. 5 is third order polynomial trend linefitted to the data points. Notably, the coefficients for the trend lineare A₁=1.891E−03, B₁=−5.551E−01, C₁=6.958E+01 and D₁=−4.572E+02.

The method further includes solving for the ratio R of the operatingspeed to the base speed:

R=N _(x) /N _(b) (N _(b) is always 1000 rpm).   (2)

Then, solving for the base torque at 1000 rpm by dividing the operatingtorque by R squared:

T _(b) =T _(x)/(R)².   (3)

Next, solving for the base CFM using equation (1) and the value of T_(b)as determined by (3) above. The CFM at the operating speed is determinedby multiplying the CFM_(b) by the ratio R:

CFM _(x) =CFM _(b)(R).   (4)

The method to solve for the torque needed to get a specific CFM includesmodeling motor CFM as a function of motor torque as provided above. Themethod further includes solving for CFM_(b) using equation (1). Thisrequires solving equation (3) for T_(b) using the programmed torqueT_(p), measured motor speed N_(m), and N_(b) base speed of 1000 RPM.

T _(b) =T _(p)/(N _(m) /N _(b))².   (5)

Also, by manipulating equation (3), the needed torque T_(x) can becalculated as follows:

T _(x) =T _(b)(R)².   (6)

Using the fan laws, R can be determined as shown below:

R=CFM _(x) /CFM _(b).   (7)

Solving for T_(x) using (1), (5) and (7) yields the desired torque:

T _(x) =T _(b)(CFM _(x) /CFM _(b))².   (8)

With reference to FIG. 6, a physical explanation of this method isprovided. The figure illustrates contours of constant CFM and SP for a10×10 blower wheel. If one assumes that this wheel requires ¾ HP at 1050RPM in a given system, then a system load line can be drawn as indicatedby the blue line. Now assume the system is configured to operate at 2000CFM. The operating point (P1) is the intersection of the 2000 CFMcontour line and the system load line. The motor is operating inconstant torque mode outputting torque (T1).

Imagine that something in the system increases the resistance to airflowand therefore increases SP. This represents a change in system loadrepresented by the short blue line. Since the motor is operating inconstant torque mode the system operating point changes to P2. One cansee that the flow is slightly different than 2000 CFM. Using the methoddescribed above one can determine the new operating point (P3) andtorque required (T2) to produce 2000 CFM.

The method to solve for SP from known speeds and torque includesmodeling SP as a function of motor torque. Suitably, SP as a function oftorque is modeled using a third-order polynomial as follows:

SP _(b) =A ₂(T _(b))³ +B ₂(T _(b))² +C ₂(T _(b))+D ₂,   (9)

where A₂, B₂, C₂, and D₂ are coefficients unique to the motor. However,higher and/or lower order polynomials are contemplated. Regardless ofthe order of the polynomial employed, modeling entails determining thecoefficients A₂, B₂, C₂, D₂.

To solve for the coefficients, a polynomial trend line of the desiredorder is fit to a corpus of data points representing the relationbetween SP and torque. Suitably, these data points are empiricallydetermined through testing. With reference to FIG. 7, a corpus of datapoints representing the relation between SP and torque is illustrated.Further illustrated in FIG. 7 is third order polynomial trend linefitted to the data points. Notably, the coefficients for the trend lineare A₂=1.362E−06, B₂=−3.675E−04, C₂=1.410E−02 and D₂=8.228E−01.

The method further includes solving for the ratio R of the operatingspeed to the base speed:

R=N _(x) /N _(b) (N _(b) is always 1000 rpm).   (10)

Then, solving for the base torque at 1000 rpm by dividing the operatingtorque by R squared:

T _(b) =T _(x)/(R)².   (11)

Next, solving for the base SP using equation (9) and the value of T_(b)as determined by (11) above. The SP at the operating speed is determinedby multiplying the SP_(b) by the ratio R²:

SP _(x) =SP _(b)(R)².   (12)

The method to solve for the torque needed to get a specific SP includesmodeling SP as a function of motor torque as provided above. The methodfurther includes solving for SP_(b) using equation (9). This requiressolving equation (11) for T_(b) using the programmed torque T_(p),measured motor speed N_(m), and N_(b) base speed of 1000 RPM.

T _(b) =T _(p)/(N _(m) /N _(b))².   (13)

Also, by manipulating equation (11), the needed torque T_(x) can becalculated as follows:

T _(x) =T _(b)(R)².   (14)

Using the fan laws to determine R², R² can be determined as shown below:

R ² =SP _(x) /SP _(b)   (15)

Solving for T_(x) using (9), (13) and (15) yields the desired torque:

T _(x) =T _(b) (SP _(x) /SP _(b))   (16)

Heat Output Leveling Means for Existing Installed Gas Furnaces andHeaters

In another embodiment, a novel concept to automatically vary and controlthe heat output of a single stage burner in existing furnaces,particularly in unitary HVAC heating systems, is described below.

All older and over 90% of the new residential hot air furnaces have aburner that turns fully on when the thermostat calls for heat. This isaccomplished by opening the solenoid operated valve in the gas supplyline. The heated air is then circulated throughout the house by a singlespeed centrifugal blower. When room temperature reaches the thermostatsetting the thermostat closes the valve thus turning the burner off.When the room cools off, the cycle repeats.

The result is that the system produces sudden cool drafts when the airis first turned on, the motor running at full speed is noisy and thetemperature is constantly rising or falling.

These undesirable effects can all be cured by installing a modulating ormulti-stage valve in the fuel supply line ahead of the main on-off valveand a variable speed blower motor. This system can be controlled to runat the rate needed to maintain an even room temperature by use of atimer which provides a gradual increase in heat and air flow until thedesired temperature is reached and then holding at that point.

Alternatively, heat and related speed can be controlled by magnitude oftemperature vs. thermostat setting differential, indoor-outdoortemperature differential, humidity, etc.

The benefits of this variable heat & air flow system include, but arenot limited to the following:

-   -   No cold drafts    -   Constant room temperature    -   Reduced motor and blower noise    -   Much less electric power to operate the motor at lower speeds    -   Better air filtering with slower air flow    -   Correcting room to room temperature differences through constant        circulation    -   Elimination of temperature layering in each room

An alternate means is to turn the primary valve on and off at a ratethat is proportionate to the thermal capacity of the heat exchanger sothat fluctuations in output air temperature is minimized.

The disclosure has been made with reference to preferred embodiments.Obviously, modifications and alterations will occur to others uponreading and understanding the preceding detailed description. It isintended that the preferred embodiments be construed as including allsuch modifications and alterations insofar as they come within the scopeof the appended claims or the equivalents thereof.

1. A method for computing and reporting cubic feet per minute (CFM) ofairflow of a motor operating at an operating speed and operating torque,said method comprising: modeling CFM of the motor as a function of motortorque to create a CFM model; calculating a ratio of the operating speedto a base speed of the motor; calculating a base torque of the motor atthe base speed from the ratio and the operating torque; calculating abase CFM of the motor from the base torque and the CFM model; and,calculating an operating CFM of the motor at the operating speed usingthe base CFM and the ratio.
 2. The method according to claim 1, whereinthe CFM is represented as a polynomial.
 3. The method according to claim1, wherein the modeling includes: receiving a plurality of data points,each data point including a torque of the motor and a corresponding CFMof the motor; and, fitting a polynomial trend line to the plurality ofmeasured data points.
 4. The method according to claim 3, wherein theplurality of measured data points are empirically determined throughtesting.
 5. The method according to claim 1, wherein the base torque isdetermined using the following equation:T _(b) =T _(x)/(R)², where T_(b) is the base torque, T_(x) is theoperating torque and R is the ratio.
 6. The method according to claim 1,wherein the operating CFM is the product of the base CFM and the ratio.7. A variable speed blower motor unit controlled by a heating,ventilation and air conditioning (HVAC) system controller, said variablespeed blower comprising: an integrated motor including a plurality ofoperating speeds or torques and an input for selecting one of theplurality of operating speeds or torques; and, an adjustment modulecoupled to the integrated motor and the HVAC system controller, whereinsaid adjustment module includes a plurality of operating modes eachassociated with one of the plurality of operating speeds or torques;wherein said adjustment module selects one of the plurality of operatingmodes on the basis of control commands received from the HVAC systemcontroller and controls the integrated motor according to the operatingspeed associated with the selected operating mode; wherein theadjustment module includes the ability to manually vary associationsbetween the plurality of operating modes and the plurality of operatingspeeds or torques; wherein the adjustment module displays operating CFMof the integrated motor as determined using the method according toclaim
 1. 8. A method for compute and reporting static pressure (SP) of amotor operating at an operating speed and operating torque, said methodcomprising: modeling SP of the motor as a function of motor torque tocreate a SP model; calculating a ratio of the operating speed to a basespeed of the motor; calculating a base torque of the motor at the basespeed from the ratio and the operating torque; calculating a base SP ofthe motor from the base torque and the SP model; and, calculating anoperating SP of the motor at the operating speed using the base SP andthe ratio.
 9. The method according to claim 8, wherein the SP isrepresented as a polynomial.
 10. The method according to claim 8,wherein the modeling includes: receiving a plurality of data points,each data point including a torque of the motor and a corresponding SPof the motor; and, fitting a polynomial trend line to the plurality ofmeasured data points.
 11. The method according to claim 10, wherein theplurality of measured data points are empirically determined throughtesting.
 12. The method according to claim 8, wherein the base torque isdetermined using the following equation:T _(b) =T _(x)/(R)², where T_(b) is the base torque, T_(x) is theoperating torque and R is the ratio.
 13. The method according to claim8, wherein the operating SP is the product of the base SP, and the ratiosquared.
 14. A variable speed blower motor unit controlled by a heating,ventilation and air conditioning (HVAC) system controller, said variablespeed blower comprising: an integrated motor including a plurality ofoperating speeds or torques and an input for selecting one of theplurality of operating speeds or torques; and, an adjustment modulecoupled to the integrated motor and the HVAC system controller, whereinsaid adjustment module includes a plurality of operating modes eachassociated with one of the plurality of operating speeds or torques;wherein said adjustment module selects one of the plurality of operatingmodes on the basis of control commands received from the HVAC systemcontroller and controls the integrated motor according to the operatingspeed associated with the selected operating mode; wherein theadjustment module includes the ability to manually vary associationsbetween the plurality of operating modes and the plurality of operatingspeeds or torques; wherein the adjustment module displays operating SPof the integrated motor as determined using the method according toclaim 8.